This sounds like a "my truck is bigger than your truck" thing. In my POCO opinion, they probably have seldom if ever dealt with expansion joints. They probably require no fittings or boxes ahead of the service point. Personally, as a former POCO inspector, I'd be fine with it. We would leave enough loop in the service drops to account for frost heave. In Alaska, heave could raise meter pedestals several inches, so trouble calls for single phase or neutral problems was VERY often due to tight U/G service wiring. But, that's assuming the utility installs the service conductors. Not always the case. I guess it's a question of who "gives" first, POCO or AHJ. Good luck! If the POCO refuses to hook you up, they probably have the bigger hammer.